Sea-going vessel equipped with two or more hulls

ABSTRACT

A sea-going vessel comprising several hulls interconnected by a deck in parallel spaced relationship, there being arranged at the prow of the vessel a wave breaking damping keellike structure extending below the water line at moulded draft and having openings for capturing the water thrown against the same and guiding said water out aft of said openings through tubes extending towards the stern of the vessel.

BEE-4.151

PATENTEU m 1 2mm SHEET -1. 0F 3 SEA-GOING VESSEL EQUIPPED TWO on MORE .HULLS. Y

creased stability 'isobtained with've'ssels of the catamaran type,'since the hulls of the vessel can-be arranged at a relatively large. distance from each other. However, certain problems of design and construction are encountered in this type of vessel, which are primarily associated-with difficulties in obtaining a sufficiently strong joining structure. between the different hulls of the vessel and the deck joining said hulls.

In an attempt to resolve these "problems'it has been suggested among otherthings, to give the hulls a deep draft, and to place the lowermost deck relatively high abovethe surface of the water. In this way the hulls of the vessel move through the water, without noticeable vertical or lateral movement. This means, however, that the forces which originate from the water thrown against the sides of the vessel create large stresses and strains, due to moments of forces, at the bridging not, however, improve these circumstances, since in the case of seas which, for instance, meetthe vessel obliquely, the

water is thrown in betweenthe hulls and upon rebounding is prevented from being thrown freely upwards or away from the side of the vessel and thus is again thrown against parts of the vessel. This means that almost all the' energy contained in the waye movement must be absorbed by the vessel.

These diff culties constructionhave meant that it has not been possible to utilize'to'the fulltheobviousadvantages afforded by vessels of the catamaran type incomparison with vessels of the conventional design, especially'with regard to large ocean-going vessels. On the other hand, it has been possible to resolve these constructional problems to some large extent, in the case of yachts, small motor boats and recreational craft for .rivers,,lakes etcgfiowever, it can be said that even in this lattercase-it has been impossible to utilize the possibilities of the catamaran to the full. Conventional vessels,

The inventor has observed that developments in sea trans-- port show that the transported units tend to become lighter. This implies that in the case of sea transport the tonnage transported influences the design of the vessel to a lesser extent, and that instead the volume becomes more and more the decisive factor. Consequently, new types of vessels must be deviced. The inventor has also observedthat a vessel well suited to the demands of increased cargo space could be obtained, if the aforementioned disadvantages in catamarans could be eliminated in a simple and effective manner,

The present invention is intended to enable the operational advantages of the catamaran to be utilized to a greater extent, and comprises a vessel having at least two hulls arranged in spaced relationship and which extend essentially parallel with one another, and one'or more decks joining said hulls, and is mainly characterized in that arranged under the deck or the lowermost deck, at least at the prow of thevessel, are one or more wave-breaking damping means which preferably extend below the water line at moulded draft and in which openings are disposed for capturing water thrown thereagainst as a result of the motion of the sea, heaving of the vessel etc., whereupon the water is caused to pass, preferably under the surface of the water, aft of the water-capturing openings through tubular through-flow members which extend from a said damping means towards the stern of the vessel.

In an advantageous development of the invention a damping means, which extends downwardly and outwardly below the water line at moulded draft from the prow of the vessel, essentially midway between two adjacent hulls,'forms together with the through-flow means, a keellike body which extends along the wholelength of the vessel and-which, aft of the damping means, is situated essentially above the water line at molded draft and, adjacent the stern of the vessel, merges with a damping means which extends downJunder the water line at moulded draft.

It is often suitable, especially in the case of very large vessels, to arrange two such keellike bodies essentially parallel to each other in side-by-side relationship.

that is to say vessels equipped with only one hull, behave differently to vessels of the catamaran type when subjected to the rolling of the sea. Thus, conventional vessels when meeting obliquely waves are caused to roll and the majority of the water projected against the side of the vessel is thrown obliquely upwards and away from the vessel. Owing to the In the case of catamarans, other forces appear which are 1 peculiar to this type of vessel, for instance when waves approaching the ship obliquely are thrownin between the hulls of the vessel, and there strike a side of thevessel. In such cases it is not possible for the water, when rebounding from the side of the vessel, to be thrown freelyupwards or outwards, but meets, for instance, the lowermost deck' joining the hulls. The greater portion of the energy stored in the wave movement must thus be absorbed by the vessel, which obtains very high stresses and strains as a result thereof. It is, of course, possible in practice to resolve the problems caused by these stresses by incorporating extra stiffening means and using a heavier con- In order to protect effectively the opposing sides of the hulls against the forces created by the waves arriving between said hulls, the damping means are preferably extended in the longitudinal direction of the vessel, so that they reach a point somewhat in front of and behind the connecting line between the prow stem and the stern post, of the vessel respectively. Contrariwise, the damping means do not extend downwards to the same depth as the hulls.

Thus, the force-absorbing damping means will prevent waves which approaching the ship obliquely astem or forward from being thrown at full force in between the hulls against the sides of the hulls in the vicinity thereof. The water is sucked into the damping means through the .openings disposed therein and then through the outgoing through-flow means in a direction towards the stern of the vessel. The openings disposed in the damping means are preferably gill-like in form and directed towards the prow of the vessel. The through-flow means preferably extend essentially rectilinearly from the forward to the after-damping means. It is also expedient, how ever, to arrange separate through-flow means provided with gill-like openings, at the merging point between the hulls and the lowermost deck joining said hulls, thereby further strengthening this portion. Additional strengthening of the structure is obtained if the lowermost deck is connected with a deck situated thereabove by means of a framework system. comprising compactly placed ribs, stringers and bulkheads.

:The through-flow means may also be given an essentially downwardly directed flaring at suitable positions between the forward and stem portion of the vessel, where cooperating, secondary waves might be expected to appear, to form extra damping means, intended to take up wave movements formed between the bulls of the vessel. These damping means should also be provided with openings, preferably gill-like openings.

To enable the damping means to dissipate effectively the forces created by the waves dashing against them without an all too robust design being necessary, ejectors or the like are arranged in the through-flow means, which suck the water forces into the openings, in a direction towards the stern. When this water is reinjected into the sea, preferably below the water line, a certain propelling force is imparted to the vessel.

Thus, the invention provides for an effective diffraction of the waves thrown between the hulls of the vessel, and wherein the bodies of water are sucked in through the openings disposed in the clamping means and forced to flow through the through-flow means towards the stern of the vessel. Since the waves are thrown against the damping means at great force, the suction effect of the ejectors arranged in the through-flow means need not be pronounced, in order that an effective through-flow of water is obtained. The energy used to operate the ejectors is at least partially regained, since the ejected water imparts a certain propelling force to the ship.

The damping means are not intended to increase the deplacement of the vessel, but since said means extends, according to the invention, a certain distance below the water line at moulded draft, a certain added displacement is obtained, whereby an additional advantageous effect is gained. When, for instance, the prow and stem sheets 'of the vessel settle after heaving and pitching the aforementioned deplacement contributes towards a more gentle settling action, whereby primarily the stresses and strains caused in the hulls and deck (s) by force moments are reduced.

The invention will now be described with reference given to the accompanying drawings, in which:

FIG. 1 shows a catamaran-here called a combimaran-provided with wave-diffracting damping means and throughflow means;

FIG. 2 shows a cross section through the combimaran, according to the invention and shown in FIG. 1; and

FIG. 3 shows, in enlarged scale and in perspective, the prow of the combimaran shown in FIG. 1.

identical elements in the FIGS. are identified by the same reference numerals.

in FIGS. 1 and 2 is shown two hulls l, 2 of a combimarian, connected together by a number of decks 3, of which the lowest deck comprises a framework system (truss system). The decks and superstructure etc. may be of any design, according to the purpose for which the vessel has been built, independently of the invention. For instance, the combimaran can be imagined as intended solely for passenger service where, especially in the case of luxury liners, large spaces are desirable. However, the combimaran according to the invention is primarily intended as a cargo vessel, in which the decks and superstructure are mainly used as storage space, and are equipped with suitable devices for loading, unloading and load-securing purposes. The vessels machinery is preferably situated at the farthest point aft, in the hulls 1, 2, while the remaining space in the hulls is used for storage purposes; the largest portion being taken up by oil tanks. The lower deck of the vessel, in the form of a framework system, is somewhat longer than the hulls l, 2, and the prow 12 is inclined sternwards, as shown at 14, so that the impact angle of the water against the prow 12 is as small as possible.

Arranged at the prow 12 of the vessel, preferably midway between the longitudinal axis of the hulls l, 2, is a wave-breaking, force-absorbing damping means 4. The means 4 departs from the prow 12 with a rounded, ,fore-and-aft contour, obliquely down towards the water line and somewhat below the same. The damping means then extends towards the stern, whereupon it rises above the surface of the water at a point somewhat aft of the connecting line between the prows of the hulls l, 2, where it merges with a through-flow means 7, directed towards the stern of the vessel, At the stern frame 13 of the hulls the through-flow means 7 merges into an after damping means 5, which corresponds with the forward damping means 4. The damping means also extends downwardly under the water line and rearwards, aft of the connecting line between the stern frame 13 of the hulls 1, 2. Disposed in the damping means 6, and possibly also along part of the throughflow means 7, are gill-like openings 6, which are directed towards the prow l2 and intended to take in water thrown against the damping means 4 and through-flow means 7. The through-flow means 7 includes one or more passages 8, which preferably present an egg-shaped cross section. To provide for an effective flow of water through the passages 8 there are arranged ejectors 11, with the assistance of which the water ejected out at 10 at a certain force, thereby imparting a certain propelling force to the vessel.

In order to strengthen the vessel still further, there are arranged at the bridging area between the hulls l, 2 and the lowermost deck 3 additional through-flow ducts 9, which also preferably present an egg-shaped cross section. The ducts 9 also present gill-like openings at the prow along a portion of their length.

Additional damping means (not shown) may also be placed between the forward 4 and aft 5 damping means at positions where cooperating, secondary waves may be expected to appear.

It may also be expedient to connect by means of ducts the through-flow passages 8 and/or the damping means 4 situated amidships with the through-flow passages 9 arranged at the bridging area between the hulls l, 2 and the bottom deck 3. In this way, and increased flow towards the stern of water taken in by the damping means 4 and the flow passages 8, 9 is obtained, whilst at the same time the hull and deck structure is further strengthened.

The damping means 4, 5 form together with the throughflow means 7 a keellike structure, which along a major portion of its length is situated above the water line at moulded draft, but in which the lower portion thereof extends at the fore and aft portions of the vessel, and possibly also at positions therebetween, below the water line at moulded draft. ln this way, in addition to breaking and damping the effect of waves striking the vessel, a reinforcing of the lower framework deck of the vessel is obtained, both fore-and-aft and athwart-ships.

lclaim:

l. A sea-going vessel, comprising at least two or more hulls arranged in essentially parallel spaced relationship, and one or more decks interconnecting said hulls, characterized in that arranged under the deck or the lowermost deck, at least at the prow of the vessel, are one or more wave-breaking damping means which preferably extend below the water line at moulded draft and in which openings are disposed for capturing water thrown against said means as a result of the motion of the sea, heaving, pitching of the vessel etc., whereupon the water is caused to pass, preferably under the surface of the water, out aft of the water capturing openings, through tubular through-flow members which extend from said damping means towards the stern of the vessel.

2. A vessel according to claim 1, characterized in that a damping means which extends downwardly and outwardly below the water line at moulded draft from the prow of the vessel, essentially midway between two adjacent hulls, forms, together with the through-flow means, a keellike structure which extends along the whole length of the vessel and which, aft of the damping means, is situated essentially above the water line and adjacent the stern of the vessel, merges with a damping means which extends downwards, below the water line of moulded draft.

3. A vessel according to claim 2, characterized in that at least two keellike structures are provided, arranged in spaced relationship and extending essentially pa'rhllel' with one another.

4. A vessel according to claim 2, characterized in that at least one of the forward damping means is situated, at least along part of its length, forward of the connecting line between the prows of the hulls.

5. A vessel according to claim 3, characterized in that at least one of the after damping means, is situated, at least along part of its length, aft of the connecting line between the sternsheets of the hulls.

6. A vessel according to claim 1, characterized in that the damping means extending below the water line have a shallower draft than the hulls. v

7. A vessel according to claim 1, characterized in that the openings in the damping means comprise gill-like openings directed towards the prow of the vessel.

8. A vessel according to claim .1, characterized in that the through-flow means inclu'deone or more tubes which sgreserit an egg-shaped cross section end which extend es ntially rectilinearly.

9. A vessel according to claim 1, characterized in that the through-flow means comprises tubes arranged at the bridging area between the hulls and the deck or the lowermost deck in such a way in the vessel that the merging portions between the hulls and deck are strengthened.

10. A vessel according to claim 1, characterized in that ejectors are arranged in the through-flow means for ejecting towards the stern water which enters the aforementioned openings. I

11. A vessel according to claim 2, characterized in that the through-flow means, at least atone position between the foremost damping means and the afterrnost damping means are flared, at least downwardly, to form additional damping means.

12. A vessel according to claim 1 1, characterized in that the additional damping means are provided with gill-like openings. 

1. A sea-going vessel, comprising at least two or more hulls arranged in essentially parallel spaced relationship, and one or more decks interconNecting said hulls, characterized in that arranged under the deck or the lowermost deck, at least at the prow of the vessel, are one or more wave-breaking damping means which preferably extend below the water line at moulded draft and in which openings are disposed for capturing water thrown against said means as a result of the motion of the sea, heaving, pitching of the vessel etc., whereupon the water is caused to pass, preferably under the surface of the water, out aft of the water capturing openings, through tubular through-flow members which extend from said damping means towards the stern of the vessel.
 2. A vessel according to claim 1, characterized in that a damping means which extends downwardly and outwardly below the water line at moulded draft from the prow of the vessel, essentially midway between two adjacent hulls, forms, together with the through-flow means, a keellike structure which extends along the whole length of the vessel and which, aft of the damping means, is situated essentially above the water line and adjacent the stern of the vessel, merges with a damping means which extends downwards, below the water line of moulded draft.
 3. A vessel according to claim 2, characterized in that at least two keellike structures are provided, arranged in spaced relationship and extending essentially parallel with one another.
 4. A vessel according to claim 2, characterized in that at least one of the forward damping means is situated, at least along part of its length, forward of the connecting line between the prows of the hulls.
 5. A vessel according to claim 3, characterized in that at least one of the after damping means, is situated, at least along part of its length, aft of the connecting line between the stern-sheets of the hulls.
 6. A vessel according to claim 1, characterized in that the damping means extending below the water line have a shallower draft than the hulls.
 7. A vessel according to claim 1, characterized in that the openings in the damping means comprise gill-like openings directed towards the prow of the vessel.
 8. A vessel according to claim 1, characterized in that the through-flow means include one or more tubes which present an egg-shaped cross section end which extend essentially rectilinearly.
 9. A vessel according to claim 1, characterized in that the through-flow means comprises tubes arranged at the bridging area between the hulls and the deck or the lowermost deck in such a way in the vessel that the merging portions between the hulls and deck are strengthened.
 10. A vessel according to claim 1, characterized in that ejectors are arranged in the through-flow means for ejecting towards the stern water which enters the aforementioned openings.
 11. A vessel according to claim 2, characterized in that the through-flow means, at least at one position between the foremost damping means and the aftermost damping means are flared, at least downwardly, to form additional damping means.
 12. A vessel according to claim 11, characterized in that the additional damping means are provided with gill-like openings. 